Sump and filter flushing in dishwashing appliances

ABSTRACT

Dishwashing appliances and methods, as provided herein, may include features or steps such as, in a standalone sump and filter flush mode, measuring a water level in the sump of the dishwashing appliance. The sump and filter flush mode also includes comparing the measured water level in the sump to a preset value and draining water from the sump when the measured water level in the sump is greater than the preset value.

FIELD OF THE INVENTION

The present subject matter relates generally to dishwashing appliances, and more particularly to features and methods for flushing a sump and filter in a dishwashing appliance.

BACKGROUND OF THE INVENTION

Dishwashing appliances generally include a tub that defines a wash chamber. Rack assemblies can be mounted within the wash chamber of the tub for receipt of articles for washing. Multiple spray assemblies can be positioned within the wash chamber for applying or directing wash liquid (e.g., water, detergent, etc.) towards articles disposed within the rack assemblies in order to clean such articles. After being applied or directed towards the rack assemblies and/or articles therein, the wash liquid generally flows by gravity to or towards a bottom of the wash chamber, such as to a sump positioned at the bottom of the wash chamber. Dishwashing appliances are also typically equipped with one or more pumps, such as a circulation pump or a drain pump, for directing or motivating wash liquid from the sump to, e.g., the spray assemblies or an area outside of the dishwashing appliance.

Over time, additional liquid may accumulate within the sump and/or liquid may remain in the sump for an extended period of time such as between operating cycles of the dishwashing appliance, in particular for dishwashing appliances that are not used frequently. If left unaddressed, this liquid may produce undesirable conditions, such as an unpleasant odor developing within the dishwashing appliance from stagnant water in the sump.

Accordingly, dishwashing appliances and methods therefor that include preventing or removing an accumulation of water, especially stagnant water, in a sump thereof would be useful.

BRIEF DESCRIPTION OF THE INVENTION

Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.

In one exemplary aspect of the present disclosure, a method of operating a dishwashing appliance is provided. The dishwashing appliance includes a sump and a filter assembly in the sump. The method includes measuring a water level in the sump of the dishwashing appliance. The method also includes comparing the measured water level in the sump to a preset value and draining water from the sump when the measured water level in the sump is greater than the preset value.

In another exemplary aspect of the present disclosure, a dishwashing appliance is provided. The dishwashing appliance includes a tub defining a wash chamber for receipt of articles for washing. A sump of the dishwashing appliance is positioned at a bottom of the wash chamber for receiving fluid from the wash chamber. The dishwashing appliance also includes a filter assembly in the sump and a controller. The controller is configured to perform a sump and filter flush mode. The sump and filter flush mode includes measuring a water level in the sump of the dishwashing appliance. The sump and filter flush mode also includes comparing the measured water level in the sump to a preset value and draining water from the sump when the measured water level in the sump is greater than the preset value.

These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures.

FIG. 1 provides a perspective view of an exemplary embodiment of a dishwashing appliance of the present disclosure with a door in a partially open position.

FIG. 2 provides a side, cross sectional view of the exemplary dishwashing appliance of FIG. 1.

FIG. 3 provides a close up, sectioned view of a sump and a pressure sensor of the dishwashing appliance of FIGS. 1 and 2.

FIG. 4 provides a sectioned perspective view of the sump of the dishwashing appliance of FIGS. 1 and 2.

FIG. 5 provides a flow chart of a method of operating a dishwashing appliance according to one or more exemplary embodiments of the present disclosure.

DETAILED DESCRIPTION

Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.

As used herein, the term “or” is generally intended to be inclusive (i.e., “A or B” is intended to mean “A or B or both”). The terms “first,” “second,” and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components. The terms “upstream” and “downstream” refer to the relative flow direction with respect to fluid flow in a fluid pathway. For instance, “upstream” refers to the flow direction from which the fluid flows, and “downstream” refers to the flow direction to which the fluid flows. The term “article” may refer to, but need not be limited to dishes, pots, pans, silverware, and other cooking utensils and items that can be cleaned in a dishwashing appliance. The term “wash cycle” is intended to refer to one or more periods of time during which a dishwashing appliance operates while containing the articles to be washed and uses a wash liquid (e.g., water, detergent, or wash additive). The term “rinse cycle” is intended to refer to one or more periods of time during which the dishwashing appliance operates to remove residual soil, detergents, and other undesirable elements that were retained by the articles after completion of the wash cycle. The term “drain cycle” is intended to refer to one or more periods of time during which the dishwashing appliance operates to discharge soiled water from the dishwashing appliance. The term “wash liquid” refers to a liquid used for washing or rinsing the articles that is typically made up of water and may include additives, such as detergent or other treatments (e.g., rinse aid). Furthermore, as used herein, terms of approximation, such as “approximately,” “substantially,” or “about,” refer to being within a ten percent (10%) margin of error.

Turning now to the figures, FIGS. 1 and 2 depict an exemplary dishwasher or dishwashing appliance (e.g., dishwashing appliance 100) that may be configured in accordance with aspects of the present disclosure. Generally, dishwasher 100 defines a vertical direction V, a lateral direction L, and a transverse direction T. Each of the vertical direction V, lateral direction L, and transverse direction T are mutually perpendicular to one another and form an orthogonal direction system.

Dishwasher 100 includes a cabinet 102 having a tub 104 therein that defines a wash chamber 106. As shown in FIG. 2, tub 104 extends between a top 107 and a bottom 108 along the vertical direction V, between a pair of side walls 110 along the lateral direction L, and between a front side 111 and a rear side 112 along the transverse direction T.

Tub 104 includes a front opening 114 (FIG. 1). In some embodiments, the dishwasher appliance 100 may also include a door 116 at the front opening 114. The door 116 may, for example, be hinged at its bottom for movement between a normally closed vertical position, wherein the wash chamber 106 is sealed shut for washing operation, and a horizontal open position for loading and unloading of articles from dishwasher 100. A door closure mechanism or assembly 118 may be provided to lock and unlock door 116 for accessing and sealing wash chamber 106.

In exemplary embodiments, tub side walls 110 accommodate a plurality of rack assemblies. For instance, guide rails 120 may be mounted to side walls 110 for supporting a lower rack assembly 122, a middle rack assembly 124, or an upper rack assembly 126. In some such embodiments, upper rack assembly 126 is positioned at a top portion of wash chamber 106 above middle rack assembly 124, which is positioned above lower rack assembly 122 along the vertical direction V.

Generally, each rack assembly 122, 124, 126 may be adapted for movement between an extended loading position (not shown) in which the rack is substantially positioned outside the wash chamber 106, and a retracted position (shown in FIGS. 1 and 2) in which the rack is located inside the wash chamber 106. In some embodiments, movement is facilitated, for instance, by rollers 128 mounted onto rack assemblies 122, 124, 126, respectively.

Although guide rails 120 and rollers 128 are illustrated herein as facilitating movement of the respective rack assemblies 122, 124, 126, it should be appreciated that any suitable sliding mechanism or member may be used according to alternative embodiments.

In optional embodiments, some or all of the rack assemblies 122, 124, 126 are fabricated into lattice structures including a plurality of wires or elongated members 130 (for clarity of illustration, not all elongated members making up rack assemblies 122, 124, 126 are shown in FIG. 2). In this regard, rack assemblies 122, 124, 126 are generally configured for supporting articles within wash chamber 106 while allowing a flow of wash liquid to reach and impinge on those articles (e.g., during a cleaning or rinsing cycle). According to additional or alternative embodiments, a silverware basket (not shown) is removably attached to a rack assembly (e.g., lower rack assembly 122), for placement of silverware, utensils, and the like, that are otherwise too small to be accommodated by the rack assembly.

Generally, dishwasher 100 includes one or more spray assemblies for urging a flow of fluid (e.g., wash liquid) onto the articles placed within wash chamber 106.

In exemplary embodiments, dishwasher 100 includes a lower spray arm assembly 134 disposed in a lower region 136 of wash chamber 106 and above a sump 138 so as to rotate in relatively close proximity to lower rack assembly 122.

In additional or alternative embodiments, a mid-level spray arm assembly 140 is located in an upper region of wash chamber 106 (e.g., below and in close proximity to middle rack assembly 124). In this regard, mid-level spray arm assembly 140 may generally be configured for urging a flow of wash liquid up through middle rack assembly 124 and upper rack assembly 126.

In further additional or alternative embodiments, an upper spray assembly 142 is located above upper rack assembly 126 along the vertical direction V. In this manner, upper spray assembly 142 may be generally configured for urging or cascading a flow of wash liquid downward over rack assemblies 122, 124, and 126.

In yet further additional or alternative embodiments, upper rack assembly 126 may further define an integral spray manifold 144. As illustrated, integral spray manifold 144 may be directed upward, and thus generally configured for urging a flow of wash liquid substantially upward along the vertical direction V through upper rack assembly 126.

In still further additional or alternative embodiments, a filter clean spray assembly 145 is disposed in a lower region 136 of wash chamber 106 (e.g., below lower spray arm assembly 134) and above a sump 138 so as to rotate in relatively close proximity to a filter assembly 210 (e.g., FIG. 3). For instance, filter clean spray assembly 145 may be directed downward to urge a flow of wash liquid across a portion of filter assembly 210 (FIG. 3) or sump 138.

The various spray assemblies and manifolds described herein may be part of a fluid distribution system or fluid circulation assembly 150 for circulating wash liquid in tub 104. In certain embodiments, fluid circulation assembly 150 includes a circulation pump 152 for circulating wash liquid in tub 104. Circulation pump 152 may be located within sump 138 or within a machinery compartment located below sump 138 of tub 104.

When assembled, circulation pump 152 may be in fluid communication with an external water supply line (not shown) and sump 138. A water inlet valve 153 can be positioned between the external water supply line and circulation pump 152 (e.g., to selectively allow water to flow from the external water supply line to circulation pump 152). Additionally or alternatively, water inlet valve 153 can be positioned between the external water supply line and sump 138 (e.g., to selectively allow water to flow from the external water supply line to sump 138). During use, water inlet valve 153 may be selectively controlled to open to allow the flow of water into dishwasher 100 and may be selectively controlled to close and thereby cease the flow of water into dishwasher 100. Further, fluid circulation assembly 150 may include one or more fluid conduits or circulation piping for directing wash fluid from circulation pump 152 to the various spray assemblies and manifolds. In exemplary embodiments, such as that shown in FIG. 2, a primary supply conduit 154 extends from circulation pump 152, along rear 112 of tub 104 along the vertical direction V to supply wash liquid throughout wash chamber 106.

In some embodiments, primary supply conduit 154 is used to supply wash liquid to one or more spray assemblies (e.g., to mid-level spray arm assembly 140 or upper spray assembly 142). It should be appreciated, however, that according to alternative embodiments, any other suitable plumbing configuration may be used to supply wash liquid throughout the various spray manifolds and assemblies described herein. For instance, according to another exemplary embodiment, primary supply conduit 154 could be used to provide wash liquid to mid-level spray arm assembly 140 and a dedicated secondary supply conduit (not shown) could be utilized to provide wash liquid to upper spray assembly 142. Other plumbing configurations may be used for providing wash liquid to the various spray devices and manifolds at any location within dishwashing appliance 100.

Each spray arm assembly 134 and 140, upper spray assembly 142, integral spray manifold 144, filter clean assembly 145, or other spray device may include an arrangement of discharge ports or orifices for directing wash liquid received from circulation pump 152 onto dishes or other articles located in wash chamber 106. The arrangement of the discharge ports, also referred to as jets, apertures, or orifices, may provide a rotational force by virtue of wash liquid flowing through the discharge ports. Alternatively, spray assemblies 134, 140, 142, 145 may be motor-driven, or may operate using any other suitable drive mechanism. Spray manifolds and assemblies may also be stationary. The resultant movement of the spray assemblies 134, 140, 142, 145 and the spray from fixed manifolds provides coverage of dishes and other dishwasher contents with a washing spray. Other configurations of spray assemblies may be used as well. For instance, dishwasher 100 may have additional spray assemblies for cleaning silverware, for scouring casserole dishes, for spraying pots and pans, for cleaning bottles, etc.

In optional embodiments, circulation pump 152 urges or pumps wash liquid (e.g., from filter assembly 210) to a diverter 156 (FIG. 2). In some such embodiments, diverter 156 is positioned within sump 138 of dishwashing appliance 100). Diverter 156 may include a diverter disk (not shown) disposed within a diverter chamber 158 for selectively distributing the wash liquid to the spray assemblies 134, 140, 142, or other spray manifolds. For instance, the diverter disk may have a plurality of apertures that are configured to align with one or more outlet ports (not shown) at the top of diverter chamber 158. In this manner, the diverter disk may be selectively rotated to provide wash liquid to the desired spray device.

In exemplary embodiments, diverter 156 is configured for selectively distributing the flow of wash liquid from circulation pump 152 to various fluid supply conduits—only some of which are illustrated in FIG. 2 for clarity. In certain embodiments, diverter 156 includes four outlet ports (not shown) for supplying wash liquid to a first conduit for rotating lower spray arm assembly 134, a second conduit for supplying wash liquid to filter clean assembly 145, a third conduit for spraying an auxiliary rack such as the silverware rack, and a fourth conduit for supply mid-level or upper spray assemblies 140, 142 (e.g., primary supply conduit 154).

In some embodiments, an exemplary filter assembly 210 (FIG. 3) is provided. As illustrated for example in FIG. 3, in exemplary embodiments, filter assembly 210 is located in the sump 138, e.g., to filter fluid to circulation assembly 150 and/or drain pump 168. Generally, filter assembly 210 removes soiled particles from the liquid that flows to the sump 138 from the wash chamber 106 during operation of dishwashing appliance 100. In exemplary embodiments, filter assembly 210 includes both a first filter 212 (also referred to as a “coarse filter”) and a second filter 214 (also referred to as a “fine filter”).

In some embodiments, the first filter 212 is constructed as a grate having openings for filtering liquid received from wash chamber 106. The sump 138 includes a recessed portion upstream of circulation pump 152 or drain pump 168 and over which the first filter 212 is removably received. In exemplary embodiments, the first filter 212 may be a coarse filter having media openings in the range of about 0.030 inches to about 0.060 inches. The recessed portion of the sump 138 may define a filtered volume wherein debris or particles have been filtered from the wash liquid by the first filter 212 or the second filter 214.

In additional or alternative embodiments, the second filter 214 is provided upstream of circulation pump 152 or drain pump 168. Second filter 214 may be non-removable or, alternatively, may be provided as a removable cartridge positioned in a tub receptacle 216 (FIG. 3) formed in sump 138.

For instance, as illustrated in FIG. 3, the second filter 214 may be removably positioned within a collection chamber 218 defined by tub receptacle 216. The second filter 214 may be generally shaped to complement the tub receptacle 216. For instance, the second filter 214 may include a filter wall 220 that complements the shape of the tub receptacle 216. In some embodiments, the filter wall 220 is formed from one or more fine filter media. Some such embodiments may include filter media (e.g., screen or mesh, having pore or hole sizes in the range of about 50 microns to about 600 microns).

When assembled, the filter wall 220 may have an enclosed (e.g., cylindrical) shape defining an internal chamber 224. In optional embodiments, a top portion of second filter 214 positioned above the internal chamber 224 may define one or more openings 226 (e.g., vertical flow path openings), thereby permitting liquid to flow into the internal chamber 224 without passing through the first filter 212 or the fine filter media of the filter wall 220 of the second filter 214.

Between the top portion openings 226 and drain pump 168, internal chamber 224 may define an unfiltered volume, e.g., when liquid flows through the openings 226 into the internal chamber 224, the liquid is unfiltered in that the liquid did not flow through the filter media of the filter wall 220. A drain outlet 228 may be defined below the top portion openings 226 in fluid communication with internal chamber 224 and drain pump 168 (e.g., downstream of internal chamber 224 or upstream of drain pump 168).

During operation of some embodiments (e.g., during or as part of a wash cycle or rinse cycle), circulation pump 152 draws wash liquid in from sump 138 through filter assembly 210 (e.g., through first filter 212 or second filter 214). Thus, circulation pump 152 may be downstream of filter assembly 210.

Drainage of soiled wash liquid within sump 138 may occur, for instance, through drain assembly 166 (e.g., during or as part of a drain cycle). In particular, wash liquid may exit sump 138 through the drain outlet 228 and may flow through a drain conduit. In some embodiments, a drain pump 168 downstream of sump 138 facilitates drainage of the soiled wash liquid by urging or pumping the wash liquid to a drain line external to dishwasher 100. Drain pump 168 may be downstream of first filter 212 or second filter 214. Additionally or alternatively, an unfiltered flow path may be defined through sump 138 to drain conduit such that an unfiltered fluid flow may pass through sump 138 to drain conduit without first passing through filtration media of either first filter 212 or second filter 214.

For example, the unfiltered flow path may extend through the openings 226, whereby liquid may flow from a filter spillway 230 and into the internal chamber 224 from the top of the internal chamber 224, e.g., without passing through the wall 220 of the fine filter 214. Such unfiltered flow path may be available so long as a maximum height of liquid in the sump 138 is above the filter spillway 230, which may occur during a first portion of the drain cycle.

During, for example, a second portion of the drain cycle, when the maximum liquid height is below the filter spillway 230, at least a portion of wash liquid within sump 138 may generally pass into internal chamber 224 through second filter 214, e.g., through filter wall 220, before flowing through drain assembly 166 and from dishwashing appliance 100. The second portion of the drain cycle may occur when the liquid level within the sump 138 has been drawn below the filter spillway 230, whereby liquid can no longer bypass the filter wall 220 of second filter 214 via the openings 226.

Although a separate recirculation pump 152 and drain pump 168 are described herein, it is understood that other suitable pump configurations (e.g., using only a single pump for both recirculation and draining) may be provided.

In certain embodiments, dishwasher 100 includes a controller 160 configured to regulate operation of dishwasher 100 (e.g., initiate one or more wash operations). Controller 160 may include one or more memory devices and one or more microprocessors, such as general or special purpose microprocessors operable to execute programming instructions or micro-control code associated with a wash operation that may include a wash cycle, rinse cycle, or drain cycle. The memory may represent random access memory such as DRAM, or read only memory such as ROM or FLASH. In some embodiments, the processor executes programming instructions stored in memory. The memory may be a separate component from the processor or may be included onboard within the processor. Alternatively, controller 160 may be constructed without using a microprocessor, e.g., using a combination of discrete analog or digital logic circuitry—such as switches, amplifiers, integrators, comparators, flip-flops, AND gates, and the like—to perform control functionality instead of relying upon software. It should be noted that controllers as disclosed herein are capable of and may be operable to perform any methods and associated method steps as disclosed herein.

Controller 160 may be positioned in a variety of locations throughout dishwasher 100. In optional embodiments, controller 160 is located within a control panel area 162 of door 116 (e.g., as shown in FIGS. 1 and 2). Input/output (“I/O”) signals may be routed between the control system and various operational components of dishwasher 100 along wiring harnesses that may be routed through the bottom of door 116. Typically, the controller 160 includes a user interface panel/controls 164 through which a user may select various operational features and modes and monitor progress of dishwasher 100. In some embodiments, user interface 164 includes a general purpose I/O (“GPIO”) device or functional block. In additional or alternative embodiments, user interface 164 includes input components, such as one or more of a variety of electrical, mechanical or electro-mechanical input devices including rotary dials, push buttons, and touch pads. In further additional or alternative embodiments, user interface 164 includes a display component, such as a digital or analog display device designed to provide operational feedback to a user. When assembled, user interface 164 may be in operative communication with the controller 160 via one or more signal lines or shared communication busses.

Turning now to FIG. 3, a close up, cross sectional view of sump 138 and a pressure sensor 200 is provided. In some embodiments, the dishwasher 100 may include a backflow preventer or check valve 240 (FIG. 4), e.g., a one-way valve, positioned at the drain outlet 228. The check valve 240 may be positioned and oriented such that the check valve 240 permits liquid flow from the sump 138 to the drain assembly 166 and restricts or prevents liquid flow to the sump 138 from the drain assembly 166.

In some embodiments, a pressure sensor 200 and a turbidity sensor 202 may be mounted to sump 138, e.g., as illustrated in FIG. 2. For instance, pressure sensor 200 may be mounted upstream of internal chamber 224 and second filter 214. Additionally or alternatively, pressure sensor 200 may be mounted downstream of first filter 212.

Pressure sensor 200 is operatively configured to detect a liquid level 1000 within sump 138 and communicate the liquid level 1000 to controller 160 (FIG. 2) via one or more signals. Thus, pressure sensor 200 and controller 160 are generally provided in operative communication.

Turbidity sensor or turbidity meter 202 is operatively configured to detect a turbidity level of the liquid within sump 138 and communicate the turbidity level to controller 160 (FIG. 2) via one or more signals. Thus, turbidity sensor 202 and controller 160 are generally provided in operative communication.

During use, pressure sensor 200 may transmit signals to controller 160 for instance, as a frequency, as an analog signal, or in another suitable manner or form that can be received by controller 160 to detect a pressure value, e.g., as a value of relative pressure or hydrostatic pressure, such as value in units of mmH₂O. In certain embodiments, pressure sensor 200 is configured to sense the height of the wash liquid above pressure sensor 200 along the vertical direction V (e.g., by detecting the pressure on pressure sensor 200).

In some embodiments, pressure sensor 200 includes a pressure plate that is generally acted on by the pressure of the wash liquid within sump 138. As the liquid level rises, the pressure plate is pushed upward along the vertical direction V and, thus, compresses air trapped within the housing and a diaphragm of pressure sensor 200. Compression may cause the diaphragm to flex or alter its position. As a result of the pressure and consequent movement of the diaphragm, a permanent magnet attached to the diaphragm may change its position in relation to a Hall-effect transducer. The transducer delivers one or more electrical signals proportional to the magnetic field of the magnet. Optionally, the signals from pressure sensor 200 may be linearized, digitized, or amplified before being sent to controller 160 for processing. Additionally or alternatively, the pressure sensor 200 may include a printed circuit board (PCB) board to electrically connect the various electrical components of pressure sensor 200. Moreover, pressure sensor 200 can be any suitable type of sensor capable of sensing the liquid level within dishwasher 100.

Turning now to FIG. 4, a sectioned perspective view of the sump is provided, with the section in this view being taken through the drain pump 168 and a check valve 240 upstream of the drain pump 168. The check valve 240 is upstream of the drain pump 168 in that the check valve 240 is, e.g., between the sump 138 and the drain pump 168, such as between the collection chamber 218 and the drain pump 168, where the collection chamber 218 is defined within the sump 138 by tub receptacle 216. Also seen in FIG. 4 is a recirculation inlet 151 which leads from the collection chamber 218 to the recirculation pump 152.

It should be appreciated that the invention is not limited to any particular style, model, or configuration of dishwasher 100. The exemplary embodiments depicted in FIGS. 1 through 4 are for illustrative purposes only. For instance, different locations may be provided for user interface 164, different configurations may be provided for rack assemblies 122, 124, 126, different spray assemblies 134, 140, 142 and spray manifold configurations may be used, different sensors may be used, such as an optical level sensor which may, in some embodiments, also be configured to measure turbidity, and other differences may be applied while remaining within the scope of the present disclosure.

Turning now to FIG. 5, an example method 400 for operating a dishwashing appliance is illustrated. Method 400 may be used to operate any suitable dishwashing appliance. As an example, some or all of the steps in method 400 may be used to operate dishwashing appliance 100 (FIG. 1). Method 400 may also be implemented, in at least some embodiments, as a sump and filter flush mode of the dishwashing appliance 100. In particular embodiments, the sump and filter flush mode may be a separate and independent mode from any or all other operations or operating modes of the dishwashing appliance, such as not part of a dishwashing cycle or included within any other cycle or mode of the dishwashing appliance. In such embodiments, the method 400 may consist of only the steps described herein and illustrated in FIG. 5 (it being understood that steps 500, 502, and 504 are shown and described to give context to the method 400 and are not part of the method 400) or only of selected steps, less than all, of the steps described herein and illustrated in FIG. 5. The controller 160 (FIG. 2) may be programmed to implement some or all of the steps in method 400.

As may be seen in FIG. 5, the method 400 may be separate and independent from dishwashing cycles, e.g., the method 400 may be a standalone mode. For example, the method 400 may begin after the end of a dishwashing cycle 500 and may continue, e.g., reiterate one or more steps of method 400, until a new dishwashing cycle is started at 502, at which point the method 400, e.g., sump and flush mode or flushing algorithm, ends and the new dishwashing cycle begins at 504. In particular, the method 400 may be automatic, e.g., may initiate after the end of the dishwashing cycle 500 and may initiate without any user input, in contrast to the dishwashing cycles which are generally user-selected cycles.

The method 400 may include, e.g., as illustrated at 402 in FIG. 5, activating a water level sensor, such as the exemplary pressure sensor 200 shown and described above. The method 400 may then proceed to a step 404 of measuring a water level in the sump of the dishwashing appliance, e.g., with the water level sensor. After measuring the water, the water level sensor, e.g., pressure sensor, is deactivated at step 406.

The method 400 may further include a step 408 of comparing the measured water level in the sump to a preset value, such as determining whether the water level in the sump is above, e.g., greater than, the preset value.

When the water in the sump is above the preset value, e.g., when the determination at 408 in FIG. 5 is positive, the method 400 may further include at least one draining step, such as step 418 and/or step 422 illustrated in FIG. 5, as will be described in more detail below. The step(s) 418, 422 of draining water from the sump may include activating the drain pump.

In various embodiments, when the water level in the sump is greater than the preset value, the method 400 may then proceed to a step 410 of activating the turbidity sensor and a step 412 of measuring a turbidity level in the sump. A step 414 of deactivating the turbidity sensor may follow the steps 410 and 412. The method 400 may further include a step 416 of comparing the measured turbidity level in the sump to a preset turbidity level, such as determining whether the measured turbidity level is greater than the preset turbidity level.

When the turbidity value is not greater than the preset turbidity level, the method 400 may then proceed directly to draining step 422 of draining a predetermined amount of water from the sump.

After step 422, the method 400 may then proceed to a delay step 424 which includes waiting for a delay period after draining the water from the sump. As illustrated in FIG. 5, the method 400 may then repeat, such as by returning to the steps 402 and/or 404 of activating the water level sensor and measuring the water level in the sump after the delay period of step 424.

When the turbidity value is greater than the preset turbidity level, the method 400 may then proceed directly to draining step 418, followed by refilling the sump, e.g., providing a flow of fill water into the sump as indicated at 420 in FIG. 5. Thus, in some embodiments, the method 400 may include draining water from the sump at step 418 after comparing the measured turbidity level to the preset turbidity level when the measured turbidity level is greater than the preset turbidity level at step 416, followed by filling the sump with a predetermined volume of water at step 420, and then proceeding to the step 422 of draining water from the sump, e.g., in some embodiments and/or some iterations, the draining step 422 may be a second chronological draining step. The fill of water in step 420 may be provided by opening a valve, such as water inlet valve 153, to provide a flow of relatively clean water from the external water supply line. The relatively clean water may be, e.g., relatively clean at least in that the water from the external water supply line is cleaner, e.g., less turbid, than the liquid in the sump prior to the drain step 418. Draining and refilling the sump at steps 418 and 420 may advantageously promote cleaning the filter and/or sump, such as by flushing out debris, e.g., food particles, from the filter and/or sump.

As noted above, the method 400 may be iterative, e.g., the method 400 may return to step 402 and the subsequent steps described above after, such as immediately or directly after, the step 408 of comparing the measured water level in the sump to the preset value and the subsequent delay period 426, or after, such as immediately or directly after, the step 422 of draining water from the sump and the subsequent delay period 424.

In at least some embodiments, method 400 may continue through one or both of the foregoing loops unless and until a user input is received. Thus, in such embodiments, the method 400 may be performed automatically, e.g., not performed in response to a user input, and may be a background process or method of the dishwashing appliance 100, e.g., the method 400 may be a background process in that method 400 runs while the dishwashing appliance 100 is not otherwise performing a user-selected or user-initiated operation, such as between dishwashing cycles. Thus, as illustrated in FIG. 5, in at least some exemplary embodiments, the method 400 may be performed after an end of a wash cycle of the dishwashing appliance, e.g., at 500 in FIG. 5, and before a beginning of a subsequent wash cycle, e.g., at 502 and 504 in FIG. 5.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims. 

What is claimed is:
 1. A method of operating a dishwashing appliance, the dishwashing appliance comprising a sump and a filter assembly in the sump, the method comprising: measuring a water level in the sump of the dishwashing appliance; comparing the measured water level in the sump to a preset value; and draining water from the sump when the measured water level in the sump is greater than the preset value; wherein the method is performed after an end of a wash cycle of the dishwashing appliance and before a beginning of a subsequent wash cycle.
 2. The method of claim 1, wherein the method is performed automatically after a user-selected cycle of the dishwashing appliance and is not performed in response to a user input.
 3. The method of claim 1, further comprising reiterating the method until a user input is received.
 4. The method of claim 1, wherein the method is a standalone mode separate and independent from any user-selectable cycles of the dishwashing appliance.
 5. The method of claim 1, further comprising waiting for a delay period when the measured water level in the sump is less than the preset value and returning to the step of measuring the water level in the sump after the delay period.
 6. The method of claim 1, further comprising measuring a turbidity level in the sump when the measured water level in the sump is greater than the preset value, and comparing the measured turbidity level to a preset turbidity level.
 7. The method of claim 6, further comprising proceeding directly to the step of draining the water from the sump after comparing the measured turbidity level to the preset turbidity level when the measured turbidity level is less than the preset turbidity level.
 8. The method of claim 6, further comprising draining water from the sump after comparing the measured turbidity level to the preset turbidity level when the measured turbidity level is greater than the preset turbidity level, followed by filling the sump with a predetermined volume of water, and then proceeding to the step of draining water from the sump.
 9. The method of claim 1, further comprising waiting for a delay period after draining the water from the sump and returning to the measuring step after the delay period.
 10. A dishwashing appliance, comprising: a tub defining a wash chamber for receipt of articles for washing; a sump positioned at a bottom of the wash chamber for receiving fluid from the wash chamber; a filter assembly in the sump; and a controller, the controller configured to perform a sump and filter flush mode, the sump and filter flush mode comprising: measuring a water level in the sump of the dishwashing appliance; comparing the measured water level in the sump to a preset value; and draining water from the sump when the measured water level in the sump is greater than the preset value; wherein the controller is configured to perform the sump and filter flush mode after an end of a wash cycle of the dishwashing appliance and before a beginning of a subsequent wash cycle.
 11. The dishwashing appliance of claim 10, wherein the controller is configured to perform the sump and filter flush mode automatically after a user-selected cycle of the dishwashing appliance and without a user input.
 12. The dishwashing appliance of claim 10, wherein the controller is configured for reiterating the sump and filter flush mode until a user input is received.
 13. The dishwashing appliance of claim 10, wherein the sump and filter flush mode is a standalone mode separate and independent from any user-selectable cycles of the dishwashing appliance.
 14. The dishwashing appliance of claim 10, wherein the sump and filter flush mode further comprises waiting for a delay period when the measured water level in the sump is less than the preset value and returning to the step of measuring the water level in the sump after the delay period.
 15. The dishwashing appliance of claim 10, wherein the sump and filter flush mode further comprises measuring a turbidity level in the sump when the measured water level in the sump is greater than the preset value, and comparing the measured turbidity level to a preset turbidity level.
 16. The dishwashing appliance of claim 15, wherein the sump and filter flush mode further comprises proceeding directly to the step of draining the water from the sump after comparing the measured turbidity level to the preset turbidity level when the measured turbidity level is less than the preset turbidity level.
 17. The dishwashing appliance of claim 15, wherein the sump and filter flush mode further comprises draining water from the sump after comparing the measured turbidity level to the preset turbidity level when the measured turbidity level is greater than the preset turbidity level, followed by filling the sump with a predetermined volume of water, and then proceeding to the step of draining water from the sump.
 18. The dishwashing appliance of claim 10, wherein the sump and filter flush mode further comprises waiting for a delay period after draining the water from the sump and returning to the measuring step after the delay period. 